Sequentially interlocked arming device

ABSTRACT

A sequentially interlocked arming device for providing the capability for the dudding of a fuze if arming events do not occur in the programmed sequence is disclosed. The sequentially interlocked arming device comprises a retardation sensor, timing delay, an out-of-line explosive train (slider), and an interlock lever which prevents the rotational movement of the slider into in-line position in the absence of a proper sequence of arming functions to prevent premature initiation of the fuze.

United States Patent 1 Bowers et a1.

[451 May 22, 1973 [54] SEQUENTIALLY INTERLOCKED ARMING DEVICE [75] Inventors: Russell E. Bowers; Norman L. Warpenburg, both of Richmond, Ind.

[73] Assignee: Avco Corporation, Richmond, 111.

[22] Filed: June 21, 1971 [21] Appl. No.: 155,064

[52] US. Cl ..102/78, 102/83 [51] Int. Cl. ..F42c 15/24 [58] Field of Search ..102/70, 76, 78, 4,

[56] References Cited UNITED STATES PATENTS 11/1967 Myers ..l02/76 R 12/1964 Weber et al. 102/78 3,316,841 5/1967 McFann et a1 102/76 R 3,515,071 6/1970 Brackman .102/78 3,614,930 lO/l971 Brackman et a1 ..102/76 R Primary ExaminerSamuel W. Engle Attorney-Charles M. Hogan et a1.

[ 5 7 ABSTRACT A sequentially interlocked arming device for providing the capability for the dudding of a fuze if arming events do not occur in the programmed sequence is disclosed. The sequentially interlocked arming device comprises a retardation sensor, timing delay, an outof-line explosive train (slider), and an interlock lever which prevents the rotational movement of the slider into in-line position in the absence of a proper sequence of arming functions to prevent premature initiation of the fuze.

9 Claims, 7 Drawing Figures PATENTEUWBZIW 3,734,022

SHEET 1 [IF 3 INVENTORS RUSSELL E. BOWERS NORMAN L. WARPENBURG ATTORNEYS SEQUENTIALLY INTERLOCKED ARMING DEVICE BACKGROUND OF THE INVENTION This invention relates to arming devices and more particularly an arming device having a sequential interlock which will cause the fuze system to fail-safe if the arming events and environments are not occurring in the proper programmed sequence.

There is a need in retardation munitions for providing fail-safe safing and arming mechanism which will prevent the munition from arming unless certain arming functions occur in a predetermined sequence. An example of such a retardation munition is a bomb fitted with high drag fins which, prior to launch and when stored on board the air craft, are folded against the bomb. Upon release, the fins open thereby causing the bomb to decelerate at a greatly increased rate so as to impact upon a target at a safe distance behind the launching aircraft. If for some reason, the deceleration forces do not occur, as where the drag fins accidentally become separated from the bomb body, it is necessary that the bomb does not become armed. If the bomb does not remain unarmed under these conditions, danger to the personnel and equipment of the launching aircraft would be created. In the case of the loss of the drag fins, it may be possible for all of the arming functions to occur, but the arming functions would not occur in the proper sequence. Under this condition it is also necessary that the fuze remain unarmed.

Accordingly, it is an object of this invention to provide a sequentially interlocked arming device which will prevent the arming of a fuze in the absence of a predetermined sequence of arming functions.

A further object of this invention is to provide means to prevent movement of a slider to the in-line armed position in the event that arming functions are not occurring in the proper programmed sequence. Another object of this invention is to provide a sequentially interlocked arming device having means to sense the bomb release from the aircraft, sense the retardation of the bomb assure that proper retardation of the bomb has occurred before arming, provide delay arming time for safe escape distance for the aircraft, and arm the bomb for detonation.

SUMMARY OF THE INVENTION This invention provides an improved sequentially interlocked arming device for preventing arming of a fuze in the absence of the proper programmed sequence of arming functions. The sequentially interlocked arming device is of simple and economical construction, has few moving parts, and is fail safe in operation. The arming device comprises a retardation sensor, timing delay, out-of-line explosive train and an interlock lever for preventing the movement of the explosive train to the in-line.(armed) position in the absence of the proper programmed sequence of arming functions.

Other objects, details, uses and advantages of this invention will become apparent as the following description of an exemplary embodiment thereof presented in the accompanying drawings proceeds.

BRIEF DESCRIPTION OF THE DRAWINGS The accompanying drawings show a present exemplary embodiment of this invention:

FIG. 1 is a side elevational view showing the frame assembly for a fuze incorporating this invention;

FIG. 2 is a bottom view of the assembly of FIG. 1 particularly showing the slider;

FIG. 3 is a top view of the frame assembly of FIG. 1 partially cut away to show pin locks;

FIG. 4 is an elevational view similar to F IG. 1 only rotated to particularly show the retardation sensing system;

FIG. 5 is a sectional view taken along line 5-5 of FIG. 1;

FIG. 6 is an elevational view similar to FIG. 4 only showing the retardation sensing system after retardation and delay; and

FIG. 7 is a sectional view similar to FIG. 5 and particularly showing the interlock lever in the armed position.

DESCRIPTION OF ILLUSTRATED EMBODIMENT Reference is now made to FIGS. 1 and 4 of the draw ings, which illustrate one exemplary embodiment of the improved sequentially interlocked arming device of this invention, which is designated generally by the reference numeral 10. The arming device is comprised of a suitable frame or housing 12 on which the retardation sensing system, shown generally as 14, is mounted.

The retardation sensing system 14 is comprised of a sensing weight 16 mounted for slidable movement on a support rod 18. Sensing weight 16 is biased by a spring 20 in the direction opposite the direction of motion of the bomb trajectory which is indicated generally by the arrow A (FIG. 1).

Mounted for slidable movement on a pair of support rods 22 and 24 is a gravity-actuated weight 26, hereinafter referred to as a G weight, and a timing block 28. The timing block 28 cooperates with a run-away escapement delay 30. A ball detent 32 carried by bushing 34 in an aperture formed in a wall of the frame assembly 12 holds the G weight in its initial position but releases it when permitted by the sensing weight 16. The G weight 26 is biased in the direction opposite the motion of the bomb trajectory by a pair of springs 36 and 38. The timing block 28 is resiliently connected to G weight 26 by a spring 40.

The sensing weight 16 is formed with an annular groove 42. A pin lock 44 mounted in the vertical wall 46 (FIGS. 3 and 5) protrudes outward into the annular groove 42 to lock the sensing weight 16 in the upper or safed position. The pin lock 44 is held in the locking position by a lanyard pull pin 48. With the lanyard pull pin 48 in place, the sensing weight 16 is restrained from movement. Lanyard pull pin 48 is disengaged from the frame 12 upon release of the bomb from the aircraft by any suitable means. When the lanyard pull pin 48 has been removed, spring 50 disengages the pin 44 from the annular groove 42 of the sensing weight 16.

i It should be understood that the configuration of the bomb or similar air-delivered projectile, including the drag fins, and their operation upon release, and the mechanism through which the bomb is released, are well known in the art and since they form no part of the invention they will not be described herein.

When the drag fins are deployed, the bomb is immediately decelerated. In response to the deceleration forces, the sensing weight 16 commits itself to perform the first of the sequentially arming functions. Sensing weight 16, in response to the deceleration forces, overcomes the restraining force of spring and bottoms itself as shown in FIG. 6. The ball 32 moves into the annular groove 42 and locks the sensing weight 16 in place. With the ball 32 disengaged, gravitational forces act on G weight 26 and overcome the biasing force of springs 36 and 38 wherein the G weight is bottomed against the end of the housing 12.

The relatively light timing block 28 is provided with a rack 52 which in turn engages a wheel 31 (FIG. 4) of the delay mechanism 30. Due to its relatively low mass, block 28 is affected relatively little by the forces of deceleration. It is, however, pulled by the spring 40 but its movement is resisted by the escape mechanism 30. Therefore, as long as the deceleration forces are larger than the spring forces acting on the G weight, the G weight will be held at the point of its furthest travel downwardly and the timing block 28 will continue to be drawn toward the G weight until the predetermined delay time, as controlled by the escapement mechanism 30, has expired. The system then releases the remaining fuze functions as the timing block is locked down in place against the G weight by a pin 54 (FIG. 3) as will be further explained hereinbelow.

The pin 54 extends through an aperture in the vertical wall 46 (FIG. 3) and engages a verge in the timer assembly 56 thereby disengaging the timer 56. The pin 54 is held in the engaging position of FIG. 3 by a timing block extension 58 (FIG. 4) extending downwardly from the timing block 28. The G weight 26 is formed with a complementary shaped groove or slot to cooperatively receive the extension 58 of the timing block 28. In the unarmed or safed position of fIG. 4, the lower end of the extension 58 is adjacent the pin 54 and holds the pin against the verge of timer S6. The extension 58 will hold the pin 54 in the engaged position until the timing block 28 has been pulled downwardly to the armed position (FIG. 6) by the spring 40 wherein the G weight 26 is bottomed against the end of frame 12 and the timing book 28 has once again been seated against the end of the G weight 26. At this point, a slot 60 in the extension 58 is aligned with the pin 54. A spring 63 then urges the pin 54 through the slot 60 thereby locking the timing block 28 and G weight against upward movement and simultaneously releasing the verge of timer assembly 56.

Any suitable commercially available timer may be utilized. In a preferred example, the timer is spring powered and is adjustable to provide different arming times. The timer is started by the removal of the pin 54 from the verge. The verge escapement is self-starting and need not receive vibration from other levers to start. The timer causes the rotation of a timing disk having a slot 64 formed therein. The disk 62 is rotat able only in one direction by the timer 56. As the disk 62 is rotated through a predetermined arc, according to the time delay set in the timer 56, a slider release arm 66 (FIG. 1) falls into the slot 64. The slider release arm is attached to a shaft 67 extending through the housing floor 68 and engages a slider 70 in a known manner to lock the slider against movement. When the arm 66 falls into the slot 64, the shaft attached to the arm 66 is displaced so as to unlock the slider 70 to thereby permit movement thereof.

The slider 70 is part of the out-of-line explosive train and is pivotally connected to the housing floor 68 by any suitable means such as screw 72. An electrical detonator and a percussion detonator, 74 and 76, respectively, (FIG. 2) are mounted in the slider 70. In the safed position the detonators are held out of-line with a firing pin assembly 78 mounted to the housing floor 68. When the slider is disengaged by the shaft attached to the slider release arm 66, torsion spring 82 causes slider 70 to rotate about its pivot 72 until the slider 70 engages the abutment wall 80. In this position, the explosive train is aligned or in the armed condition. The spring 82 holds the slider in the armed position so that the percussion detonator is aligned with the firing pin 78. The firing pin 78 may be a pin stab type detonator causing detonation of the detonator 76 upon impact. As the slider is moved to the armed position, the electrical detonator 74 is brought in line over its respective lead (not shown) connecting the detonator 74 to any suitable electrical circuit such as a proximity type sensing circuit or the like. In response to an electrical impulse, the electrical detonator 74 is detonated. As can be seen, in the preferred embodiment herein described, the explosive train maybe initiated by either the electrical detonator or the percussion detonator, In some instances, one or the other of the detonators may be removed to provide specialized detonation functions.

The housing floor 68 is formed with an aperture 84 therethrough. A shaft 86 extends through the aperture 84 and is secured to the slider 70 for movement therewith. An interlock lever 88 is pivotally mounted by a pin 90 in a slot 92 formed in the vertical wall 46. Referring now to FIG. 5, it is seen that one end 94 of the lever 88 is substantially U-shaped and the shaft 86 is cradled thereby. The other end 96 of the lever 88 protrudes through the slot 92 into the area defined by the timing block 28. In the safed or unarmed position, the lever 88 is prevented from clockwise rotation (FIG. 5) by engagement of the lever end 96 with the timing block 28. In order to arm the fuze, the slider 70 must be rotated as hereinabove described to align the explosive train. Rotation of the slider 70 will cause shaft 86, secured perpendicular to the sliders plane of motion, to be likewise rotated in a clockwise direction, as seen in FIG. 5. The interlock lever 88, as a result of the cradling effect of the end 94 about shaft 86, will also be moved clockwise about the pivot pin 90. If the timing block 28 has not been locked in place by the pin 54 as previously described, the lever end 96 will engage the timing block 28 thereby preventing rotation of the lever 88. Should the timing block 28 have completed its downward movement, the lever 88 will be free for rotational movement about pin 90. Hence, the interlock lever 88 cannot complete its rotation unless the retard system timing block 28 has completed its part of the arming cycle. FIG. 7 shows the position of the shaft 86 and lever 88 in the armed condition after rotation of the slider to the in-line position.

It is seen that in the event the slider is released prior to the completion of the arming sequence, the slider will be unable to complete the arming cycle and the fuze will remain in the unarmed or safed condition. Thus, the interlock lever 88 through its cooperation with the shaft 86, prevents the fuze from arming except by the correct arming sequence. Thus, if the programmed sequence for arming the safety and arming device is out of sequence; i.e., any failure of a component which releases the slider prior to its set time, will cause the interlock to function and block the slider from moving to the armed position.

An indicating disk 98 may be attached at one end of the shaft 86 to provide a visual indication of the fuze through a window (not shown) on the fuze, whether the fuze is armed or unarmed.

In the event the drag device or retard fins should not function or should break away from the bomb such that the retardation forces do not occur for the proper length of time, the G weight 26 and timing block 28 will not be locked in the down or armed position shown in FIG. 6. In this event, the springs 36 and 38 will overcome the gravitational forces and urge the G weight 26 and timing block 28 upward, hence, the timing block 28 will prevent rotational movement of the lever 88. The slider then is maintained in the out-of-line position so that the fuze is maintained in the safed condition to prevent detonation on impact or on signal from a target detecting device.

It can be seen that the sequentially interlocked arming device of this invention prevents arming of a fuze in the absence of a proper sequence of arming functions. Accordingly, this invention accomplishes the objectives hereinbefore set forth.

While a present exemplary embodiment of this invention has been illustrated and described, it will be recognized that this invention may be otherwise variously embodied and practiced by those skilled in the art.

What is claimed is:

1. In a free fall munition, a sequentially interlocked arming device for preventing the movement of an outof-line explosive train to the in-line position in the absence of the proper programmed sequence of arming functions including a predetermined duration of sensed deceleration forces comprising:

a retardation sensing weight responsive to deceleration forces, said weight moving in the direction of free fall in the presence of deceleration forces of a sufficient magnitude acting on the munition;

a G weight mounted for movement parallel to said sensing weight, said G weight being displaced in the direction of free fall during deceleration of the munition due to fall retardation; a timing block mounted for movement complementary with said G weight, said timing block having first and second positions;

delay means relatively interconnecting said timing block with said G weight for moving said timing block from the first to the second position in response to movement of said G weight, said means controlling the duration of movement of said timing block from the first to the second position;

a slider forming part of an explosive train, said slider having an unarmed and armed position in which the explosive train is respectively out-of-line and in-line;

lock means securing said slider against movement from the unarmed position to the armed position prior to said timing block reaching the second position, said lock means being responsive to said timing block wherein said slider is unlocked for movement when said timing block reaches the second position; and

interlock lever means mounted relative to said slider, said lever means relatively cooperating with said slider and being engageable with said timing block wherein said lever means engages said timing block to prevent movement of said slider to the in-line armed position prior to said timing block reaching the second position.

2. The arming device according to claim 1 in which said interlock lever means further comprises a shaft mounted to said slider in a plane perpendicular to the movement of said slider and a lever in which one end of said lever is substantially U-shaped and is pivotally mounted to cradle said shaft for coaction therewith.

3. The arming device according to claim 2 in which sald slider is pivotally mounted about a first axis of rotation for rotational movement about said axis point and in which said lever is pivotally mounted for rotation about a second axis displaced from said first axis wherein rotational movement of said slider causes said shaft to pivot said lever about said second axis whereby said shaft is uncradled in in-line position.

4. In a fail-safe safing and arming device for installation in a bomb of the type including fall retardation means, a sequentially interlocked arming device for preventing the movement of an out-of-line explosive train to the in-line position in the absence of the proper program sequence of arming functions comprising:

a housing;

a sensing weight mounted to said housing for relative movement thereto, said weight adapted to respond to deceleration forces caused by fall-retardation thereby displaced in the direction of flight;

a G weight normally biased in the position opposite the direction of fall of the bomb, said G weight displaced in the direction of flight during deceleration caused by the fall-retardation;

a timing block mounted for movement complementary with said G weight;

delay means for controlling the duration of movement of said timing block;

a spring connecting said timing block with said G weight wherein said timing block is pulled towards said G weight when the G weight is displaced in response to the fall retardation;

a slider forming part of an explosive train mounted to said housing, said slider having an unarmed position in which the explosive train is out of-line;

interlock means mounted on said housing providing relative mechanical interconnection between said slider and said timing block wherein said slider is locked in the unarmed position and prevented from moving to the armed position when said interlock means is engageable with said timing block whereby said slider is locked in the unarmed position during the duration of movement of said timing block and wherein said interlock means is not engageable with said timing block after said duration of movement whereby said slider is unlocked for movement; and

means for moving said slider from the unarmed position to the armed position when said slider is unlocked by said-interlock means.

5. The arming device according to claim 4 in which said interlock means is a lever pivotally mounted to said housing, one end of said lever being engageable with said timing block in the unarmed condition and during the duration of movement of said timing block, and the other end of said lever relatively cooperating with said slider for locking and unlocking said slider for movement.

6. The arming device according to claim 5 further comprising a shaft mounted to said slider in a plane perpendicular to the movement of said slider and in which the other end of said lever cooperatively engages said shaft.

7. The arming device according to claim 6 in which said slider is pivotally mounted about a first axis of rotation for rotational movement about said axis and in which said lever is pivotally mounted for rotation about a second axis displaced from said first axis, said other end of said lever being substantially U-shaped wherein said shaft is cradled by the U-shaped end of said lever wherein rotational movement of said slider causes said shaft to pivot said interlock lever about the second axis whereby said shaft is substantially uncradled in the armed position.

8. The arming device according to claim 7 further comprising:

lock means for locking said sensing weight against movement prior to discharge of the bomb carrying the arming device;

a displaceable balance detent locking said G weight against movement, said sensing weight urging said balance detent into locking engagement with said G weight prior to movement of said sensing weight in response to deceleration forces, detent receiving means formed on said sensing weight for receiving said balance detent when said sensing weight is displaced in the direction of flight by the deceleration forces thereby unlocking said G weight for movement, said balance detent locking said sensing weight in its displaced position during movement of said G weight.

9. The arming device according comprising:

a timer delay;

slider lock means responsive to said timer delay for locking said slider against rotational movement in the absence of the time delay interval;

a lock pin disengaging said timer, said lock pin being held in locking position by said timing block wherein said lock pin is disengaged from said locking position at the end of the duration of movement of said timing block.

to claim 8 further 

1. In a free fall munition, a sequentially interlocked arming device for preventing the movement of an out-of-line explosive train to the in-line position in the absence of the proper programmed sequence of arming functions including a predetermined duration of sensed deceleration forces comprising: a retardation sensing weight responsive to deceleration forces, said weight moving in the direction of free fall in the presence of deceleration forces of a sufficient magnitude acting on the munition; a G weight mounted for movement parallel to said sensing weight, said G weight being displaced in the direction of free fall during deceleration of the munition due to fall retardation; a timing block mounted for movement complementary with said G weight, said timing block having first and second positions; delay means relatively interconnecting said timing block with said G weight for moving said timing block from the first to the second position in response to movement of said G weight, said means controlling the duration of movement of said timing block from the first to the second position; a slider forming part of an explosive train, said slider having an unarmed and armed position in which the explosive train is respectively out-of-line and in-line; lock means securing said slider against movement from the unarmed position to the armed position prior to said timing block reaching the second position, said lock means being responsive to said timing block wherein said slider is unlocked for movement when said timing block reaches the second position; and interlock lever means mounted relative to said slider, said lever means relatively cooperating with said slider and being engageable with said timing block wherein said lever means engages said timing block to prevent movement of said slider to the in-line armed position prior to said timing block reaching the second position.
 2. The arming device according to claim 1 in which said interlock lever means further comprises a shaft mounted to said slider in a plane perpendicular to the movement of said slider and a lever in which one end of said lever is substantially U-shaped and is pivotally mounted to cradle said shaft for coaction therewith.
 3. The arming device according to claim 2 in which sa1d slider is pivotally mounted about a first axis of rotation for rotational movement about said axis point and in which said lever is pivotally mounted for rotation about a second axis displaced from said first axis wherein rotational movement of said slider causes said shaft to pivot said lever about said second axis whereby said shaft is uncradled in in-line position.
 4. In a fail-safe safing and arming device for installation in a bomb of the type including fall retardation means, a sequentially interlocked arming device for preventing the movement of an out-of-line explosive train to the in-line position in the absence of the proper program sequence of arming functions comprising: a housing; a sensing weight mounted to said housing for relative movement thereto, said weight adapted to respond to deceleration forces caused by fall-retardation thereby displaced in the direction of flight; a G weight normally biased in the position opposite the direction of fall of the bomb, said G weight displaced in the direction of flight during deceleration caused by the fall-retardation; a timing block mounted for movement complementary with said G weight; delay means for controlling the duration of movement of said timing block; a spring connecting said timing block with said G weight wherein said timing block is pulled towards said G weight when the G weight is displaced in response to the fall retardation; a slider forming part of an explosive train mounted to said housing, said slider having an unarmed position in which the explosive train is out of-line; interlock means mounted on said housing providing relative mechanical interconnection between said slider and said timing block wherein said slider is locked in the unarmed position and prevented from moving to the armed position when said interlock means is engageable with said timing block whereby said slider is locked in the unarmed position during the duration of movement of said timing block and wherein said interlock means is not engageable with said timing block after said duration of movement whereby said slider is unlocked for movement; and means for moving said slider from the unarmed position to the armed position when said slider is unlocked by said interlock means.
 5. The arming device according to claim 4 in which said interlock means is a lever pivotally mounted to said housing, one end of said lever being engageable with said timing block in the unarmed condition and during the duration of movement of said timing block, and the other end of said lever relatively cooperating with said slider for locking and unlocking said slider for movement.
 6. The arming device according to claim 5 further comprising a shaft mounted to said slider in a plane perpendicular to the movement of said slider and in which the other end of said lever cooperatively engages said shaft.
 7. The arming device according to claim 6 in which said slider is pivotally mounted about a first axis of rotation for rotational movement about said axis and in which said lever is pivotally mounted for rotation about a second axis displaced from said first axis, said other end of said lever being substantially U-shaped wherein said shaft is cradled by the U-shaped end of said lever wherein rotational movement of said slider causes said shaft to pivot said interlock lever about the second axis whereby said shaft is substantially uncradled in the armed position.
 8. The arming device according to claim 7 further comprising: lock means for locking said sensing weight against movement prior to discharge of the bomb carrying the arming device; a displaceable balance detent locking said G weight against movement, said sensing weight urging said balance detent into locking engagement with said G weight prior to movement of said sensing weight in response to deceleration forces, detent receiving means formed on said sensing weight for receiving said balance detent when said sensing weight is displaced in the direction of flight by the deceleration forces thereby unlocking said G weight for movement, said balance detent locking said sensing weight in its displaced position during movement of said G weight.
 9. The arming device according to claim 8 further comprising: a timer delay; slider lock means responsive to said timer delay for locking said slider against rotational movement in the absence of the time delay interval; a lock pin disengaging said timer, said lock pin being held in locking position by said timing block wherein said lock pin is disengaged from said locking position at the end of the duration of movement of said timing block. 